曲面基底衍射光学元件的激光直写技术

Laser Direct Writing Technique of Diffraction Optical Element on Curved-Surface Substrate

飞秒激光直写技术(FsLDW)因其优异的三维加工能力、高空间分辨率、低附加损伤等优点被广泛地应用于微纳加工领域,但传统飞秒激光直写技术在加工效率、加工面积和加工精度之间存在矛盾。为了实现高速、大面积、高精度的激光微纳加工,构建了一种由大范围水平位移台和高速旋转台组成的极坐标系飞秒激光直写系统。基于该系统,研究了轴对称样品中心对准方法及曲面曲率校准方法,并在曲面上制备了多阶三维结构。最终完成了在透镜曲面上制备直径为10mm的衍射圆光栅结构,实现了飞秒激光高速、大尺寸、高精度地制备大面积三维结构。该研究为高性能折衍混合光学元件的制备提供了有力的技术支持。

Femtosecond laser direct writing （FsLDW） has been widely applied in the field of mico-nano fabrication for its advantages such as excellent three-dimensional processing ability, high spatial resolution and low additional damage. However, there are contradictions between machining efficiency, machining area and machining accuracy in the conventional FsLDW. In order to realize high speed, large area and high precision in the process of laser micro- nano fabrication, we have built a new FsLDW system based on polar coordinates, which is composed of large scale horizontal linear stages and high speed rotary stage. The approaches for the alignment of axisymmetric samplers center and the calibration of surface curvature have been investigated based on the proposed system, and a multilevel three-dimensional structure has been fabricated on a curved surface. Finally, a diffractive circle grating structure with diameter of 10 mm has been fabricated on curved surface of the lens, and the femtosecond laser fabrication of large area three-dimensional structure with high speed, large scale and high precision has been realized. The research provides strong technical support for the fabrication of high performance hybrid refractive-diffractive optical element.